The backlight module is among important components of a liquid crystal display. Since the liquid crystal is non-luminous itself, the backlight module is required for supplying light with sufficient brightness and uniform distribution for the liquid crystal display, such that the liquid crystal display can display images normally.
As is shown in FIG. 1, a traditional backlight module comprises a light source 2′ and a light guide plate 1′, wherein the light source 2′ is located at one side of the light guide plate 1′ at the light incident surface. In operation, the light emitted from the light source 2′ enters the light guide plate 1′ through the light incident surface of the light guide plate 1′, and exits via the light emergent surface of the light guide plate 1′ after being reflected by the bottom surface of the light guide plate 1′, thereby providing the display with uniform backlight. At present, the adjustment of the brightness of the display is mainly achieved by adjusting the current flowing through the light source in the backlight module, which may easily cause an undesired impact on the service life of the light source.